The white fuses should be 10 A, and you should have 4 fuses for headlights.
This, unfortunately. But you could straight swap the rubbish fusebox it has for any generic one, with some lenghts of wire. Maybe this image will shed some light on the wiring:
True. Speedometer is mechanical.
In regards with the latest mishap, I'm afraid your pressure plate is past it's best. It usually happens suddenly. To check if this is the problem, and not a bent gearchange fork, try to start it while having selected 2nd, and put your foot down: if it's just like a failing clutch disk (lots of slipping), but on top of that you can't change gears with the engine started, it's the plate.
To adjust the clutch cable you can work at the end linked to teh gearbox, if I remember correctly it should be an open-ended 10 mm spanner.
There are two types of clutches on those: 180 and 200 millimeters clutch disk diameter. Don't know which one you have, if it's 1289 cubic centimeters it should be the 180, but I think you can use whichever. Anyhow, the code for the 180 mm one from LuK is 618017106
EDIT: Mr. Pastry is right, nobody took the gearbox out for a clutch job on those when doing it in a backyard. Always bonnet out, and then engine out. Usually done with the help of two or three neighbours.
Here you have a way better manual than the one you have (looks dodgy, but if you wait with that page opened for a full minute there will be a "download file" button, which will reward you with a 64 MB pdf of a 400 page book) : https://vdocuments.net/download/automobile-dacia-diagnosticare-intretinere-reparatie
The problem is you'd have to learn Romanian